Question

I am afraid it is a really stupid question but I do not get it. I’m contructing a std::string that contains a line feed (needed for further processing) this way:

std::string mystr=std::string("\n")

Amazingly mystr is empty afterwards. And when I step into the string-constructor the handed over data are empty too (so no \n contained). What is wrong here?

Answer 1

The string should not be empty, it should have size 1. What leads you to believe it is empty?

#include <iostream>
#include <string>

int main()
{
  std::string s1 = std::string("\n");
  std::string s2;
  std::cout << s1.size() << "\n";
  std::cout << s2.size() << "\n";
}

output 1 and 0.

What could be confusing you is a copy elision or a move construction in this expression:

std::string s1 = std::string("\n");

which one would normally write like this anyway:

std::string s1("\n");